Figure 1.

(Top) Waveform (T2) and spectrograms of each of the three stimulus conditions (T2, T2′, T4) illustrate the experimental paradigm used to acquire cortical responses. The waveform shows robust periodicity within the pitch segment for T2. The vertical white, dashed line at 500 ms demarcates the transition from the initial noise segment to the final pitch segment. CPRs were extracted from evoked responses beginning with pitch onset. F₀ contours (white) are superimposed on their respective pitch segments. T2 (rising) and T4 (falling), respectively, represent exemplary citation forms of Mandarin Tone 2 and Tone 4. T2′ (flipped variant of T2) exhibits a rising pitch contour similar in pitch direction to T2. Yet T2′ does not occur in the Mandarin tonal space Across stimuli, spectrograms show clear resolution of dynamic, rising or falling spectral bands corresponding to the harmonics of the fundamental frequency. (Bottom) In addition to changes in pitch direction, pitch contours are differentiated phonetically by changes in the location of peak acceleration (early vs. late). T2 and T4 (solid line) share the same acceleration trajectory throughout their duration. Both T2 and T4 reach a peak of acceleration late in the pitch contour; T2′ (dashed line), in contrast, reaches a peak early in the pitch contour.